The recent release of macOS 10.15.2 had some additional updates to the Xprotect yara rules within it. After reviewing what changed in the yara rules I decided to dig a little deeper into how Xprotect gets called. Jonathan Levin’s excellent book MacOS and iOS Internals, Volume III: Security & Insecurity briefly talks about Gatekeeper and Xprotect but didn’t have the internals I was looking for. I ended up finding Patrick Wardle’s excellent presentation from the 2015 Virus Bulletin Confer...